In general, wires are constituted of a metal part, i.e., a current-carrying conductor, and an insulative jacket surrounding the exterior of the conductor to protect the conductor and withstand operating voltage. Particularly, PVC is mainly used as a material of the insulative jacket because PVC has advantages such as economic efficiency, due to low cost, superior processability, and flame retardancy. However, PVC and the like, which include a halogen compound such as chlorine, generate toxic gases, such as dioxin and hydrogen chloride, which are toxic to the environment and humans, during an incineration process. These gases are also known carcinogens. Accordingly, use of resins including a halogen-based flame retardant is being regulated, whereby research into a jacket material that can replace such resins is underway. Particularly, as a substitute for a PVC cable, a polyolefin cable including metal hydroxide, such as magnesium hydroxide or aluminum hydroxide, as a non-halogen flame retardant is being used. However, since such a flame retardant containing metal hydroxide should be disadvantageously used in a large amount to exhibit sufficient flame retardancy, flexibility, elongation, and other properties required in a cable are deteriorated.
In connection with this, a thermoplastic polyether ester elastomer resin having superior mechanical strength, chemical resistance, heat resistance, and weather resistance is being used in various industries. However, since such a thermoplastic polyether ester elastomer resin has poor flame retardancy, utilization thereof has been relatively limited. Accordingly, methods of using the thermoplastic polyether ester elastomer along with a flame retardant so as to provide flame retardancy to the thermoplastic polyether ester elastomer have been developed.
However, when a flame retardant is added to the polyether ester-based elastomer resin, mechanical properties, such as tensile strength, elongation rate, and heat resistance, of a resin are deteriorated. To address such property deterioration, a flame retardant should be added in a minimal amount. However, when the flame retardant content is decreased, flame retardancy is not exhibited. Therefore, there is an urgent need for development of a method of securing sufficient flame retardancy while lowering the content of a flame retardant used in the polyether ester-based elastomer resin and preventing property deterioration due to application of a flame retardant.